Andrew P.wrote a review of Black Diamond Mercury Mitten on February 26, 2017
Familiarity: I've used it several times
After years of being unhappy in winter because of damaged rock climber fingers that get cold easily, I finally bought a few quality pairs of gloves this year. I got these mitts for the coldest weather as the consensus seemed to be that they're pretty warm. They certainly are and the several times I've needed them for skiing or otherwise they've really saved the day (and my hands). I think there are probably warmer options for when it's REALLY cold, but as long as I'm not just sitting around, these work pretty well even in the low single digits. My hands have stayed warm in them while skiing in wind chill that was well below 0° F, probably because of the nice Pertex shell material. I have, however, been cold in them in the low single digits whilst being relatively inactive; there are limits to their insulating ability. They resist water very effectively and the liners are really, really comfortable, making the mitts a joy to wear. The split-finger design of the liner seemed strange at first, but I really only use it when I want a tiny bit more dexterity (which is otherwise poor, obviously) and there's plenty of room to skip the separate finger and keep all four together in the other liner compartment. Gloves might be a better choice for certain activities, but with my (cold) hands these mitts will continue to have an important place in the gear lineup during wintertime.